Certainly there are hot-button political issues involved, including the Democrats' aim to make President Trump look bad if he separates illegal alien families who cross into the U.S.

Democrats, meanwhile, accuse the president of using the invasion to divert attention from their talking points on health care.

The origin of the caravan, however, likely won't become clear until it's revealed who is coordinating the campaign.

"They're trying to make this look organic, but it can't be! It can't be organic! Something like this has to be planned," Limbaugh said. "And so I'm asking myself, who's behind the planning? I've asked the question, well, they have to eat. Well, they have to use the bathroom. Well, there's some kids there without their parents," he said Monday.

He said "rich Democrat donors" anxious to embarrass the president could be behind it.

"It could be that they want to demonstrate the cold-heartedness and the mean-spiritedness of Donald Trump by having him do what he said he would do, not let them in. Basically shut down the border. If the Democrats are thinking that, man, oh, man, do they not get it," he said.

Limbaugh said that for Democrats to get a political boost from the caravan, something bad would have to happen to someone in it.

Then, he said, the media and the Democrats could blame Trump.

Otherwise, he said, the caravan is "a microcosm" of what got Trump elected.

He said Democrats may also be hoping Trump will do nothing about it.

"They might be rolling the dice that Trump isn't gonna do anything because they think they've rattled Trump with their stories earlier this year about how he separated families at the border and how Trump didn't like that narrative and didn't want it to last so he did what he could to change it."

No matter the politics, there is someone behind the scenes "making this happen," he said.

"We've got how many? Two-thousand miles? Stop and think of this. From Honduras to the southern border of United States, Arizona, is around 2,000 miles. Seven thousand people one day just decided to start walking to the United States 2,000 miles."

He said another possibility is that the drug cartels are involved.

"But there has to be political involvement here, too, because money has to be available. There has to be money being spent on this. So you've got 7,000 people who all of a sudden decide, all of a sudden, 'cause nobody saw this coming. And there was no advance word of it. Seven thousand people decide to start walking 2,000 miles."

He described the necessary accommodations for such an entourage.

"We don't see pictures of where they're using the bathroom. We don't see pictures of them gathering or getting food and eating it. I mean, look, in random video you might see some people chewing things, but we don't see how this is being handled. We don't see the Porta-Potties. We don't see. ... And are they just urinating in rivers and streams, and what would the environmentalist wackos think about that if that's happening?" he wondered.

"Every time you see a caravan, or people illegally coming, or attempting to come, into our Country illegally, think of and blame the Democrats for not giving us the votes to change our pathetic Immigration Laws!" Trump tweeted Monday morning. "Remember the midterms! So unfair to those who come in legally."

He said police south of the border apparently are unable to stop the movement and warned "Middle Easterners" may be in the mix, noting ISIS members have been caught in the region in recent years.

Sadly, it looks like Mexico’s Police and Military are unable to stop the Caravan heading to the Southern Border of the United States. Criminals and unknown Middle Easterners are mixed in. I have alerted Border Patrol and Military that this is a National Emergy. Must change laws!

Trump called it a national emergency and said the military has been notified.

Guatemala, Honduras and El Salvador were not able to do the job of stopping people from leaving their country and coming illegally to the U.S. We will now begin cutting off, or substantially reducing, the massive foreign aid routinely given to them.

"This is a foreign invasion, whether they're armed or not. Some of them, no doubt, are. The U.S. military is perfect. We could send the military anywhere on our border to deter any invasion, military or otherwise. We're not violating any law here. That's exactly what this is, and it must be looked at that way."

"Amusingly, liberals bullied the Associated Press on Sunday into correcting one of its headlines after the wire service described the caravan as an 'army of migrants,'" he wrote. "'A ragged, growing army of migrants resumes march toward US,' read the original headline on the AP story. The AP later changed the headline to replace the word 'army' with 'caravan.'"

Agency France-Presse reported Secretary of State Mike Pompeo's concerns that the migrants "may be victimized by human smugglers or others who would exploit them.

And he also cited the "apparent political motivation of some organizers."

Guatemalan President Jimmy Morales said more than 5,000 migrants had entered Guatemala from Honduras, AP reported, but that some 2,000 had since returned home on a fleet of government-chartered buses."

Over the weekend, Mexico opened its border.

AP reported a caravan leader was working with Pueblo Sin Fronteras, or People Without Borders.

But the reporters on the scene of the march did not explain who is paying for supplies and other expenses.

But the report didn't address the costs of the caravan, noting only that one resident was handing out free sandals to the travelers.

USA Today reported the throng now estimated at 7,000 continues to defy President Trump's warning.

"Trump's threats have done little to dissuade members of the caravan from trying to reach the U.S. border to make their claims for asylum. Members of the group have become so insistent on staying together, in fact, that they've been turning down medical aid and offers of bus rides to ensure that they continue on as a group," the report said.

"But my question about this caravan: Who is feeding these people? They have to eat. This is a long walk. This is the Honduran version of Trail of Tears, right? Who is feeding these people? Where are they bathing? Where are they showering? They've been doing this for a week now. They are coming here ostensibly to escape poverty," he said at the time.

"Well, who is feeding them along the way? Who is providing, what shall we say, hygienic services? Where all these people going to the bathroom? Somebody has to have planned for this. This kind of thing as a spontaneous combustion-type event? They wouldn't have made it this far if there weren't somebody feeding them and if there weren't services for them along the way.

"Another migrant caravan is on its way to the United States, and once again we're told that it is not a political stunt," he wrote. "It is repeatedly stated by these poor 'marchers,' as well as everyone on the left, that they are just trying to escape the violence of their countries. However, these facts make this a bit harder to believe."

He pointed out some U.S. cities have as much crime as San Pedra Sula and Tegucigalpa.

"So it would seem the trek to the United States is more dangerous than just staying home."

He also wondered: "Who is organizing these 'marchers'? They don't just happen organically."

Furthermore, he wondered: "Who is coaching these marchers? Is it once again Pueblo Sin Fronteras, the George Soros funded group who bankrolled the April 2018 march to the border, or is it Honduran communist Bartolo Fuentes, looking to cause upheaval to regain power in his country?"

"Who is funding the migrant 'caravan'? Each migrant's passage can cost as much as $7K each. Per capita income Honduras is $2.3 K. It is doubtful that such sums came from the kiddies' college funds. Evidence of Soros funding of an earlier 'spontaneous' migration have been found among the tentacles of support that flow from his Open Society group coffers," he wrote.

He said some of the participating groups "are funded by George Soros' Open Society Foundation."